After a newly launched satellite has reached its operational orbital altitude, it is necessary to perform a series of comprehensive tests to confirm that all components of the communications subsystem have survived the rigors of launch, and that the initial in-orbit performance is meeting design specification. A regime of such tests is generally referred to as Payload In-Orbit Test or simply Payload IOT. Traditional beginning of life Payload IOT is comprised of a series of dedicated and specific RF measurements. Following successful completion of the Payload IOT campaign, which includes a detailed manual comparison of the measured RF parameters against pre-launch predicts to ensure performance is being met, the satellite is accepted from the manufacturer and is ready to be placed into commercial service. Depending on the complexity of the communications payload design and IOT system capabilities, Payload IOT can typically require many weeks to complete. Once placed into commercial service, Payload IOT measurements may be repeated on an as-required basis should further in-orbit performance evaluation be warranted.
Traditional Payload IOT on increasingly complex payloads is impractical without the existence of sophisticated ground-based test systems and teams of technical experts to oversee their operations and to review all measured data. These systems consist of racks of computer-controlled RF test equipment which interface to specialized calibrated ground antennas (often in multiple geographical regions) to generate conditioned radio frequency (RF) signals. These signals provide the capability to accurately measure the RF parameters that are used to technically assess payload subsystem performance. FIGS. 1A-1C present a block diagram of a typical hardware configuration and RF equipment racks for a Payload IOT ground station transmit (uplink) and receive (downlink) chain. In addition to ground antennas and transmission/reception equipment, such a test system typically requires a complex arrangement of RF signal synthesizers, power meters, signal analysers, phase shifters, phase combiners and controllers on the transmit chain, to generate a known uplink signal, and a similarly complex arrangement of complementary analysis components on the receive chain. While there have been advances in RF test equipment, software automation and network interfacing, the RF measurement techniques have remained relatively unchanged for many decades. Thus today, the standard procedure is to perform a comprehensive set of highly specific measurements, to independently measure key RF performance parameters, whenever there is a requirement to ensure that the satellite communications subsystem in-orbit performance is meeting specification.
The Payload IOT process in use today within the industry has become increasingly complex due to the continued belief that traditional RF measurement methodologies are still warranted to effectively validate the in-orbit performance of complex, multi-purpose satellite communications payloads. Despite further enhancements in Payload IOT system capabilities, there is little to be gained in terms of reducing the time, effort and manpower requirements for planning and conducting a Payload IOT campaign with the continued use of traditional RF measurement methodologies. Therefore, with each passing year, it has become more and more difficult to plan, coordinate, conduct, and complete the technical results review of a Payload IOT campaign within acceptable timeframes that are required to meet, often critical, corporate commercial objectives.
Satellite-related components and resources are very costly. Because of the time and resources required by traditional Payload IOT there is a need for improved systems and methods for validating the in-orbit operation and performance of a satellite's communications subsystem.